1. Field of the Invention
This invention relates in general to airport weather information systems and in particular to a method for transmitting real-time weather information from a ground station to an airplane.
2. Description of the Prior Art
One of the problems associated with either the landing at or the taking off from an airport which is not manned, is the lack of pertinent and up-to-date information on the conditions at the airport. Such information includes real-time weather information and other information which can be exclusive to particular airports.
When an aircraft approaches an airport for a landing, the pilot must know both the wind direction and the wind speed if he is to land safely. If the airport is uncontrolled, the pilot must first fly over the airport and observe the windsock to make a judgment as to the present wind direction. However, this is very wasteful as it often takes up to ten minutes of extra flying time to perform this maneuver. Also, this maneuver can be quite dangerous in the event of a low overcast.
In the landing of a jet aircraft, the present outside temperature should also be available to the pilot. A jet aircraft takes off and lands by its indicated air speed which is determined by the weight of the aircraft and the outside temperature. If the pilot is not informed of the present outside temperature, he must estimate this temperature in order to determine the indicated air speed of the aircraft. A miscalculation of the indicated air speed can result in a jet aircraft using a larger portion of the runway than is necessary. Thus, if the pilot of a jet aircraft is informed of the present outside temperature, he can determine the correct indicated air speed for landing and consequently use less runway and fuel.
One apparatus for providing an aircraft with weather information has been disclosed in U.S. Pat. No. 3,949,399 issued to Huber et al on Apr. 6, 1976 and entitled "Automatic Direction Finding Equipment For Airplanes." A weather transducer is connected to a recording system such that, when the pilot generates the appropriate control signal to the system, the weather information is transmitted to the pilot in speech form. However, this apparatus is not capable of analyzing the signals from the weather transducer to provide the pilot with information such as the variation in wind direction or the speed of the wind gusts.